Conventionally, a fallboard of the above-mentioned type has a rear end thereof hinged to a fallboard support. The fallboard is rotated about a hinge for opening and closing of the same. Particularly, to close the fallboard, it is pulled forward and rotated until the bottom of a front end thereof contacts or rests on the top of a keyslip. This manner of closing/opening the fallboard has an inconvenience that if the closing operation is not properly carried out, the fallboard rotates with force by gravity to bump against the keyslip, so that a damage can be caused to the keyslip or fallboard, or user's finger(s) can be caught between the fallboard and the keyslip.
To eliminate the inconvenience, a closing control device is provided for the fallboard, one conventional type of which is comprised of a slow closing device which is formed by a one-way torque hydraulic damper and fixed to an arm or keybed of the piano, and a linkage connecting between the slow closing device and the fallboard. According to the construction of the conventional closing control device, when the fallboard is rotated in a closing direction, the braking force of the slow closing device acts on the fallboard via the linkage to cause the fallboard to close slowly.
However, the conventional closing control device suffers from a problem of difficulty in fulfilling the requirement of JIS (Japanese Industrial Standards) S 8507-1975 prescribing a manner of mounting and removing of the fallboard. That is, the JIS defines that the fallboard of the upright piano should permit mounting and detachment thereof without using any tool or the like. In the conventional closing control device, however, the slow closing device is fixed to the arm or keybed forming part of the body of the piano, and linked to the fallboard via the linkage, so that in detaching the fallboard from the body of the piano, it is required to separate at least component parts connected to each other at one point of a chain of connected component parts arranged between the fallboard and the slow closing device. Therefore, to fulfill the requirement of the JIS, the closing control device should be constructed such that the component parts to be separated are separable from each other without using any tool or the like. The closing control device thus constructed, however, suffers from the inconvenience that these separable component parts tend to be disconnected when the fallboard is opened and closed, so that it is difficult to open and close the fallboard in a stable manner.